diff --git a/src/nostalgia/studio/lib/undostack.hpp b/src/nostalgia/studio/lib/undostack.hpp
index 71bc6426..e7e021d5 100644
--- a/src/nostalgia/studio/lib/undostack.hpp
+++ b/src/nostalgia/studio/lib/undostack.hpp
@@ -42,6 +42,7 @@ class UndoStack {
 
 		ox::Signal<ox::Error()> redoTriggered;
 		ox::Signal<ox::Error()> undoTriggered;
+		ox::Signal<ox::Error()> changeTriggered;
 };
 
-}
\ No newline at end of file
+}